The giant water reservoir was discovered in the Tarim Basin. The basin located in China’s northwestern Xinjiang province, which covers about 350,000 square miles, is one of the driest places in China.

The area of the water reservoir is roughly the size of Egypt. The scientists actually made the discovery while investigating carbon dioxide absorption by the region.

According to Professor Li Yan of the Xinjiang Institute of Ecology and Geography, the water in the underground reservoir could be much more than scientists estimate. The water itself is too salty therefore it cannot be used in households.

“A 2014 study in Nature Climate Change, which found that the Mojave Desert acts as a carbon sink, suggested that the world’s deserts might play a role similar to oceans and forests in soaking up and storing some of the excess carbon emissions from human activity,” Discovery reported.